1. Field of the Invention
The present invention relates to a plasma display panel.
2. Background of the Related Art
A variety of flat display apparatuses, that have reduced the apparatus weight and volume, i.e., the disadvantages of a cathode ray tube, have been developed. These flat display apparatuses include a Liquid Crystal Display (LCD), a plasma display panel, a Field Emission Display (FED), Electro-Luminescence (EL) and the like. The plasma display panel is a display device that employs a gas discharge method, and can be easily manufactured in a large size and can display images of high luminance.
FIG. 1 is a plan view illustrating a plasma display panel in the related art. FIG. 2 shows a discharge cell of the plasma display panel shown in FIG. 1.
Referring to FIGS. 1 and 2, the discharge cell of the plasma display panel includes an address electrode 12X formed on a lower substrate 18, and a sustain electrode pair formed on an upper substrate 10, i.e., a scan electrode 12Y and a sustain electrode 12Z.
On the lower substrate 18 having formed the address electrode 12X thereon is formed a lower dielectric layer 22 for accumulating wall charges thereon. Barrier ribs 24 are formed on the lower dielectric layer 22. Phosphor 20 is coated on the surfaces of the lower dielectric layer 22 and the barrier ribs 24.
The barrier ribs 24 function to prevent ultraviolet rays generated by a discharge and a visible ray from leaking to neighboring discharge cells. The phosphor 20 is excited with ultraviolet rays generated by a gas discharge and generates any one visible ray of red, green or blue. An inert gas for gas discharge is injected into a discharge space formed by the upper substrate 10, the lower substrate 18 and the barrier ribs 24.
Each of the scan electrode 12Y and the sustain electrode 12Z formed on the upper substrate 10 has a transparent electrode 12a and a bus electrode 12b, and intersects the address electrode 12X.
Each of the transparent electrodes 12a is formed of a transparent conductive material to allow light supplied from the discharge cell to pass through. A bus electrode 12b is formed of a metal material having a low resistance.
An upper dielectric layer 14 and a protection film 16 are sequentially formed on the upper substrate 10 on which the scan electrode 12Y and the sustain electrode 12Z are formed. Wall charges generated during a discharge are accumulated on the upper dielectric layer 14.
The protection film 16 functions to prevent damage to the upper dielectric layer 14 due to sputtering generated during the discharge of plasma and also to enhance emission efficiency of secondary electrons. The protection film 16 is generally formed using Magnesium Oxide (MgO).
In the related art plasma display panel, after a discharge cell is selected by a counter discharge between the address electrode 12X and the scan electrode 12Y, a discharge is sustained by a surface discharge between the scan electrode 12Y and the sustain electrode 12Z. The phosphor 20 radiates a visible ray with ultraviolet rays generated when the discharge is sustained in the discharge cell. Gray levels can be implemented by controlling a period where a discharge is sustained in the discharge cell.
In the related art, however, there is a problem where a discharge is not generated even though a driving voltage is applied to discharge cells located in corner regions of the plasma display panel. That is, in an exhaust process of exhausting air and/or impurities (e.g., particles of MgO) within the discharge space toward the outside, or an injection process of injecting an inert gas, a foreign substance is adhered on the surfaces of the scan electrode 12Y and the sustain electrode 12Z of the discharge cell. A foreign substance remaining on the surfaces of the scan electrode 12Y and the sustain electrode 12Z hinders a plasma discharge. As a result, the foreign substance causes a problem in that a discharge is not generated even though a driving voltage is applied to a discharge cell.